(1) Field of the Invention
The invention relates to a separator for separating out fatty and oily substance particles from kitchen waste air and other gas currents and to a waste air duct specially designed for use with such a separator.
(2) Prior art
For separating out particles of fatty substances or the like, more specifically from the waste air of catering kitchens, separator units, generally full of loose solids or having a solid material bed filter, are placed in the duct coming from the draw-off hoods. As commonly put to use, such separators may have sieve walls forming limiting structures, between which a solid material bed is placed which may be made up of active carbon with the necessary grain size and which takes up the fatty substance particles in the air which goes through the separator.
One important shortcoming of such separators, in addition to a comparatively high specific resistance to flow, is that if the waste air to be separated has a great amount of undesired materials in it, the take-up effect of the bed of solids quickly comes to an end and the separator hardly has any further effect and acts only as a structure stopping the current of air from moving freely through the system. When the bed of solids is fully saturated, the separator or the bed of solids has to be replaced. If this need is overlooked, something which is frequently the case because of the working conditions in a kitchen, the particles of fatty substances will go as far as the part of the waste air duct forming the outlet of the separators. It is for this reason as well that public authorities make it necessary for certain safety measures to be taken for seeing to it that there is no danger of fire in the duct running from the separator, and taking such safety measures is a complex process.